Under floor HVAC systems carry conditioned air through a plenum located beneath the floor of an occupied space. The conditioned air flows into the occupied space via one or more air diffuser terminals mounted in openings in the floor. The air diffuser terminals are located at various positions in the floor to distribute the conditioned air evenly within the occupied space. In modular floor configurations, the air diffuser terminals may be relocated to accommodate changes in the work layout of the room, increased or decreased worker capacity, or changes in the intended utilization of the occupied space. Accordingly, it is useful in the art to have an HVAC air diffuser terminal that may be readily relocated within the occupied space. Because such air diffuser terminals are floor mounted, the air diffuser terminals must be securely mounted in the floor to ensure the safety of the occupants.
Typical floor mounted HVAC air diffuser terminals include a basket, a diffuser grille, and a mounting flange. The mounting flange secures the air diffuser terminal in the opening in the floor or other support structure. Conditioned air from the under floor air plenum is delivered to the occupied space above the floor through the basket and the diffuser grille. In some installations, the modular terminal basket includes a stationary round basket and rotatable internal round basket. Both the stationary basket and the rotatable basket have openings in their sides and bottoms, such that rotation of the internal basket relative to the stationary basket opens and closes the openings to control the amount of air that flows through the terminal basket, the diffuser grille, and into the occupied space. The internal rotatable basket is connected to the diffuser grille so that rotation of the diffuser grille opens and closes the openings and thereby controls the amount of air flowing through the floor terminal. U.S. Pat. No. 6,290,596 issued to Birdsong, discloses a modular floor terminal with a stationary basket and a rotatable basket connected to the diffuser grille.
The air diffuser terminal disclosed in Birdsong '596 is secured the floor opening by gripping engagement of the upper floor surface and the lower floor surface between a trim ring extending around the periphery of the diffuser grille and a retaining ring, respectively. The retaining ring is rotated with respect to the trim ring such that cammed grooves urge the retaining ring against the lower floor surface while drawing the trim ring downwardly against the upper floor surface. A latching mechanism on the retaining ring engages with latching teeth of the trim ring to prevent rotation and thereby disengagement of the retaining ring.
While the Birdsong '596 air diffuser terminal may be installed and secured in the floor opening by a worker position above the floor, the design of the retaining ring and trim ring interface is unnecessarily complicated.